Process for improving soiling characteristics of hydrophobic textile material

ABSTRACT

A process for improving the soiling characteristics of hydrophobic textile material which comprises applying thereto an aqueous solution comprising a hydrophilic water dispersible polymer and irradiating the textile material. Products are also included.

United States Patent Inventor Appl. No. Filed Patented Assignee PROCESS FOR IMPROVING SOILING CHARACTERISTICS OF HYDROPI-IOBIC TEXTILE Greville Machell [50] Field of Search l 17/ 1 39.5 Spartanhurg,S.C. C, 139.5 R, 138.8 F, 143 R,145,l66,l61Ul1-l.161 ,707 01-115, 165,93.31,161 UlC, 161 1U,161 UHN,161 KP; July 20, 1967 i 204/159.l5; 8/115.6 Nov. 16, I971 Deering Milliken Research Corporation References Cited Spartanburg, S.C. UNlTED STATES PATENTS 2,955,961 10/1960 Koller 117/161 X 3,236,685 2/1966 Caldwell et al. 117/138.8

Primary Examiner-William D. Martin Assistant Examiner-Theodore G. Davis Attorneys-Norman C. Armitage and H. William Petry MATERIAL 5 Claims, No Drawings 1.8. CI ..l17/139-5CQ, ABSTRACT: A process for improving the soiling chm-acll7l93.31, l17/l38 .8 F, 117/143 A, teristics of hydrophobic textile material which comprises ap- 117/ 139.5 A plying thereto an aqueous solution comprising a hydrophilic Int. Cl 844d l/50, water dispersible polymer and irradiating the textile material.

D06m 15/08 Products are also included.

PROCESS FOR IMPROVING SOILING CHARACTERISTICS OF HYDROPI-IOBIC TEXTILE MATERIAL BACKGROUND OF THE INVENTION The present invention is directed to a process for improving the soiling characteristics of textile material containing hydrophobic constituents and the resulting products.

Textile material containing synthetic constituents, which are of the minimum care, hydrophobic genus, possess an affinity for attracting and tenaciously holding oily soil. Such materials, and particularly polyester/cotton materials, have gained prominence in the textile industry, but the greatest single disadvantage is probably their soiling characteristics. As the use of these blends in garments, etc., increases, the soiling problem becomes more and more significant. The polyester constituent of the blend is hydrophobic and has a great affinity for soil, especially oil-bome soil. Once the polyester becomes soiled, the removal of the soil by normal laundering techniques, i.e., washing in a home washer with a specified amount of detergent, is almost impossible due to the hydrophobic characteristics of the fiber. In other words, once the soilbecomes ingrained in the polyester, the hydrophobic properties thereof prevent the ingress of water which is required to remove the soil or the attraction between the soil and the fiber is sufficiently strong that water will not remove the soil. Likewise, any soil that is removed from the polyester/cotton blend in the normal wash cycle has an affinity for redeposition onto the textile material before completion of the wash cycle. This redeposition is compounded with each wash, and accordingly, the material becomes progressively darker or dingier with succeeding washes. These soiling characteristics normally found in textile material containing both cellulosic and noneellulosic, synthetic, hydrophobic materials soon render the article or garment unacceptable for wear.

From the genesis of polyester materials, numerous attempts have been made to solve the previously discussed soiling problems. These attempts, however, have been mainly directed to the concept of rendering the textile material, e.g., fabric or garments soil resistant. In other words, attempts have been made to treat the textile material in such a manner that the soil will not become affixed thereto. Generally speaking, such attempts while possibly successful to a degree in tending the fabric soil resistant, also adversely affect the fabric in numerous ways whereby the process is unacceptable from a commercial standpoint.

PRIOR ART U.S. Pat. No. 2,999,774 to Schappel features the utilization of silica particles and a salt of a multivalent metal for the purpose of rendering a fabric soil resistant. U.S. Pat. No. 2,734,835 to Florio et al., employs at least two hydrous stable metal oxides selected from aluminum silica, titanium, beryllium, cerium, cobalt, germanium, manganese, tin, zinc and zirconium. U.S. Pat. No. 3,089,778 to Pierce et al., teaches the utilization of a water-insoluble basic aluminum salt having an ultimate particle size of less than 0.5 microns US. Pat. No. 2,992,943 to Coover et al., while not purely related to inorganic materials is directed to the prevention of dry soiling only. In other words, the Coover et al. treatment dictates the use of a water-soluble compound (an alkyl titanate and an organic solvent) and to obtain the desired soil resistant properties requires a dry cleaning process to clean the material.

The organic approach to the soiling problem of synthetic fiber containing fabrics also has been attempted. U.S. Pat. No. 3,236,685 to Caldwell et al., render a fabric antistatic and soilresistant by coating a fabric with a solution or solutions containing a polymeric acid defined as containing -COOH, -SO=H and/or -PO H, groups. Additionally, a compound containing a polyol or a compound having incorporated therein epoxide groups is included which under proper conditions reacts with the acid to form an ester. U.S. Pat. No.

3,152,920 to Caldwell et al., is a complement of the above patent wherein, instead of reacting the polymeric acid with a polyol or an epoxide, the polymeric acid is reacted with the reaction product of a polyol and a polyisocyanate. U.S. Pat. No. 3,090,704 to Collins et al., is directed to a terpolymer for rendering a fabric soil resistant consisting of (l a compound having a cross-linking component, (2 a compound having an anionic component, e.g., an alkali metal salt of an aromatic sulfonic acid and (3 a compound having a strong nonionizable, norihydratable permanent or induced dipole. U.S. Pat. No. 2,876,141 to Matthews employs a solution containing (1 mineral oil, (2 base cordage oil, (3 oleic acid and (4 a cationic wetting agent, e.g., trimethyl-B-oleamidocthyl ammonium sulfate to improve the soil resistance of fabric.

Irradiation techniques for polymer combinations have been suggested. For example, U.S. Pat. No. 3,075,904 to DAlelio teaches the irradiation of a linear, aliphatic, saturated polymeric ester substrate in the presence of a polyunsaturated modifier. Miller, U.S. Pat. No. 2,895,891 teaches that certain nonsalt containing cellulosic compounds will cross-link under the influence of ionizing radiation when in a wet state. Additionally, numerous patents are directed to the irradiation treatment of monomeric or polymeric materials.

DESCRIPTION OF INVENTION In contrast to the above, the present invention is directed to a process for improving the soiling characte tics of a textile material containing a hydrophobic constituent which comprises applying to the textile material an aqueous solution comprising a hydrophilic, water dispersible polymer and then subjecting the textile material to irradiation. The hydrophilic polymer is believed to form an insoluble, cross-linked, hydrophilie film around the constituents of the textile material, facilitating removal of soil from the textile material and also decreasing redeposition of soil from wash water onto the material.

The textile material may include cellulosic fibers for example, cotton, paper, linen, jute, flax, regenerated cellulosic fibers including viscose rayon, and the like. The present invention is particularly useful for textile material containing both cellulosic as well as noncellulosichydrophobic fibers, particularly fibers having minimum care characteristics of own. For example, mixtures of cellulosic fibers with synthetic polymeric fibers such as polyesters, including poly(ethylene terephthalate); polyamides, e.g., poly(hexamethylene adipamide); acrylic fibers, including polyacrylonitrile and copolymers containing about percent or more combined acrylonitrile; polyolefins, such as polyethylene, polypropylene, and the like are acceptable.

The process of the present invention may likewise be applied to natural polymeric substrates, for example, keratin fibers, particularly wool. Such fibers also may be blended with synthetic polymeric fibers as desired.

The advantages of the process of the present invention are evident whether the textile material is treated in the form of fibers, yarns, threads, or fabrics. such fabrics can be woven, nonwoven, knitted, printed, dyed or otherwise treated prior to irradiation or thereafter as desired.

The hydrophilic water dispersible polymer useful in the process of the present invention to improve the soil release and soil redisposition properties of textile material are polymers consisting essentially of one or more of the following where R, and R are selected from the group consisting of 3 S;M and Q-aom where M is hydrogen, an alkali metal or ammonia; provided R and R are not hydrogen simultaneously;

where R is selected from the group consisting of H and where R R and R are selected from the group consisting of Cl-l C H and --CH Cl-l Ol-l, provided R R, and R are not hydrogen simultaneously.

The following list is exemplary of suitable polymers that may be employed according to the present invention;

polyacrylic acid polyvinyl alcohol hydroxyethyl cellulose methyl cellulose acrylic acid/sodium styrene sulfonate copolymer polyethylene oxide polypropylene oxide copolymer of ethylene oxide and propylene oxide polyvinyl pyrrolidone polyacrylamide water-soluble polyurethanes made from a polyalkylene ether glycol and a diisocyanate, and terminated in -OH.

Some of the polymers set forth above require preswelling prior to irradiation e.g., polymers typified by Group III, such as methyl cellulose and hydroxyethyl cellulose. If these polymers are not preswelled, degradation may result during irradiation, rendering the product unsatisfactory. Other polymers are more useful if preswelled, e.g., polyvinyl alcohol. Such polymers may be preswelled in water and applied as an aqueous solution to the textile material. They are then irradiated in the wet state.

A further criterion for the hydrophilic polymers is that the molecular weight of the polymers be more than about 25,000. If the molecular weight is lower, durable soil release and/or soil redeposition characteristics may be achieved. The upper limit for molecular weight of the polymers is governed primarily by viscosity and ease of application.

Polymers that may be employed in practicing the present invention may be applied to the textile material in any suitable manner. Exemplary are the various means for applying polymers to textile material including padding, spraying dip coating, knife coating, printing and the like. Of these methods, padding preferred.

In preparing a pad bath for applying the hydrophilic polymer, the bath need only contain the polymer, water and a wetting agent, if required. However, if additional properties are desired for the textile material, such as wash and wear characteristics or durable press properties then textile resin or other appropriate chemicals for imparting these properties may be added to the pad bath. Preferably, when utilizing polymers that do not have to be preswelled the textile material is dried after padding and before irradiation. Drying prior to irradiation of the textile material is preferred since irradiation in the wet state tends to impart stiffness to a fabric. According'ly, depending upon the use of the fabric an its requisite hand, either a wet or dry state irradiation process may be employed. With polymers that must be preswelled, however, irradiation is conducted in the presence of the swelling agent for the particular polymer.

The polymers maybe successfully employed according to the teachings of the present invention over a wide range of concentrations. It should be noted that there is a direct relationship between the amount of polymer applied to the textile material and its ability to release soil or to prevent redeposition of soil. Preferably, however, the process is practiced to provide a pickup of at least 0.1 percent on the dry weight of the fabric, with the upper limit being dictated by the ultimate use of the fabric, bearing in mind that the more polymer added to the fabric, the stiffer the hand.

The irradiation of the textile material may be accomplished in any desirable manner. The term irradiation" as used herein refers to that energy which is propagated through space, the possibility of propagation not being conditioned on the presence of matter, as distinguished from mere mechanical agitation in materials such as is characteristic of the energy produced by sonic or ultrasonic transducers, although the speed, direction and amount of energy transferred may be less effective as a result of the presence of matter. The level of radiation used in accordance with the present invention is that having sufficient energy to remove an electronic gas atom forming an ion pair. The source of radiation is not critical to the present invention although differences and particular radiation sources may require a different procedure for practicing the present invention. Exemplary of sources of irradiation are electrons, protons, neutrons, alpha particles and the like from the high energy particle sources. Furthermore, ionizing electromagnetic radiation sources such as gamma rays, X- rays and the like are likewise useful and may be used in practice of the present invention. Thus, the source of radiation may be an isotope such as cobalt 60, cesium I37, etc., or apparatus in which an electron accelerator is employed along with a scanner to provide the desired radiation does to a textile material.

Radiation dosages within the range of L000 to 100,000,000 rads may be utilized, a rad being defined as the amount of high energy irradiation that leads to an energy absorption of l00 ergs in the absorbing material. The preferred range of radiation dosage lies between about 0.l megarads and I0 megarads and most preferably between 1 and 4 megarads.

As previously stated, if the textile material is in a wet state when irradiated, the aesthetic properties thereof are affected, specifically, the hand of the fabric is stiffened. For example, at moisture levels above about 40 percent by weight, a somewhat stiff product is produced, whereas at moisture levels between about 5 and 30 percent and preferably below about 15 percent, a satisfactory hand is achieved in the final product. If, however, the textile material is to be used in drapes, upholstery fabrics, tablecloths, and the like, a somewhat stiffer hand may be acceptable, and for these particular end uses, the intermediate step of drying the textile material prior to irradiation may be omitted.

The dosage of irradiation referred to above does not refer to the dose rate emitted by the irradiation source, but refers to the total dosage. It may be advantageous to use a low does rate from the irradiation source and make several passes of the material past the irradiation source to produce the total does level desired. On the other hand, the emission from the irradiation source may be increased and the number of passes decreased. One factor which may affect the choice is the particular textile material being employed.

The process of the present invention, as discussed above, may be used with a process designed to impart either wash and wear or durable press characteristics to textile fabrics. ln the event wash and wear characteristics are desired, the textile resin or other material used to impart wash and wear characteristics may be applied with the hydrophilic cross-linkable polymer of the present invention. The irradiation step is then conducted after which the textile material is heated under textile curing conditions to produce wash and wear characteristics. For durable press properties, the various chemical may be applied and thereafter the textile material is subjected to irradiation. A garment or article is prepared from the textile material and while held in a desired position, the treated material is subjected to curing conditions, etc., providing the garment or article with a memory of the particular configuration in which it is held during curing.

The following examples illustrate procedures for practicing the present invention but are not intended to limit the scope of the invention. Unless otherwise stated, parts and percentages are by weight.

EXAMPLE I Swatches cut from polyester/cotton (65/35 fabric to a size about 12x37 inches are soaked in 4 percent solutions of hydrophilic water dispersible polymers that are prepared as follows:

A. Elvanol 72-60, polyvinyl alcohol sold by E. l. du Pont De Nemours and Company, is added slowly to cold water at a temperature of 2030 C. while stirring at high speeds. Stirring is continued for about minutes after the polyvinyl alcohol has wetted out. The mixture then is heated at 90 C. with a steam bath until the polyvinyl alcohol dissolves.

B. Bordens polyacrylic acid (25 percent solids) is diluted with water to prepare a 4 percent solution.

C. A copolymer of acrylic acid-sodium styrene sulfonate (90/10) is diluted with water to prepare a 4 percent solution.

D. Cellosize WP-09, hydroxyethyl cellulose marketed by Union Carbide, is added slowly to water containing a few drops of Syn-Eac 905, a condensation product of 9.5 moles ethylene oxide per mole of nonyl phenol, marketed by Sylvan Chemical Company, as the water is being stirred.

E. Methocel 65HG, methyl cellulose marketed by Dow Chemical Company is added to about one-third of a quantity of hot water at a temperature of 80-90 C. as the water is being agitated. The agitation is continued until the methyl cellulose is completely wetted out. The remaining two-thirds of the water is then added at room temperature and mixture is agitated until solution is complete.

F. Polyox WSRN-80, polyethylene oxide sold by Union Carbide, is added slowly to water containing a few drops of Syn-Fae 905 as the water is being agitated.

After soaking the polyester/cotton swatches in the various solutions prepared above for a sufficient time to insure complete wetting of the fabric, the fabric samples are passed through padding rolls operating at 40 pounds per square inch pressure to provide a wet pickup of approximately 50 weight percent. The fabric samples are placed on a pin frame and irradiated to a total dose of about 2 megarads (two passes under the electron accelerator at a speed of about 48 feet per minute with a dosage rate of about 1.0 megarads per pass). Each of the irradiated samples is then dried at 105C. for 1% minutes, pressed for 5 seconds under steam, 2 seconds under bake and 5 seconds under vacuum, and finally cured at 305 F. for about minutes. Each of the samples of treated fabric is then divided into two equal portions and tested for improved soil redeposition properties by subjecting the same to dirty washes as described below.

One portion of each of the samples is placed in an automatic washing machine filled to the high water level with hot water (140 C.) and 1% cups of Tide, a commercial detergent sold by Proctor and Gamble. A soil solution, prepared as follows is then placed in a lOO ml. beaker at the position where water returns to the wash tub from the filter. The soil solution is so positioned to insure its distribution throughout the wash water to provide even application of dirt, if any, to the fabric samples.

The soil solution is prepared by placing 10 grams of used dry cleaning powder, 15 grams of Squibb mineral oil, 1 gram of No. 6 fuel oil and 1 gram of Tide in a ml. beaker. Fifteen grams of warm water are then added to the contents of the beaker after which stirring insures good mixing of the contents of the beaker.

The fabric samples are washed a total of five times following the above procedure and then tumble dried. An untreated control included in the five washes is used as a comparison with the treated samples. Results are recorded in table I. The samples are then subjected to 5 additional dirty washes as described supra, yielding the results shown in table ll.

TABLE I Soil Redeposition Study After Five Washes of Various A rating of 5.0 indicates a while fabric and progressively decreasing numbers represent a progressively more dirty fabric.

TABLE ll Soil Redeposition Study After Ten Washes of Various Polymers Cross-Linked on 65 35Dacron/Cotton by Irradiation Wet No.Dirty" Polymer Pickup,% Washes Rating A 54 10 1.5 B 5| [0 1.5 C Sl l0 l.5 D 48 I0 [.0 F. 55 10 3.0 F 51 I0 L0 Control 10 0' The control is much more heavily soiled than any of the treated samples.

The remaining portions of each of the samples are subjected to 10 dirty washes and then 10 clean" washes (without the soil solution in the wash water). As a final treatment, these samples are subjected to one additional dirty wash after the l0 clean washes. The samples show no significant improvement over the first group of samples, and in fact are a little more dirty. This test indicates that the soil redeposited on the fabric cannot later be removed by normal washing, even l0 normal washings. Ratings of the second group of samples are recorded in table lll.

TABLE III Soil Redeposition Study After Dirty Washes Followed by Clean Washes of Various Polymers Cross-Linked on 65/35 Dacron/Cotton by Irradiation Wet No.Dirly" No. "Clean" Polymer Pickup, Washes Washes Rating A 54 ll [0 3.0 B 51 ll 10 3.5 C 51 l I I0 3.5 D 48 l I I0 2.0 E 55 ll l0 4.5 F 5| H l0 [.5 Control I 1 l0 0 The eleventh dirty" wash is the 21st wash. Control is given 0 rating and the best sample (6) is given a 5.0,

Other samples are rated numerically according to comparison with the two standards.

Gel formation generally occurs in a film formed of the polymer after being subjected to irradiation. Also, the polymer becomes water insoluble, at least to some degree, while retaining its hydrophilic characteristics. The following example indicates subjectively the degree of gellation of film formed by varying percent solids solution.

EXAMPLE I] A 25 percent aqueous solution of polyacrylic acid sold by Borden is diluted with water to prepare solutions having the concentrations indicated in table lV. Thin layers of each of the solutions are placed in a glass dish and subjected to irradiation dosages as indicated in table IV.

Samples 7 and 8 are post heated at 100 C. for 10 minutes. Samples 10, ll and 12 are dried to film at 95 C. for 30 minutes prior to irradiation. All of the samples are then immersed in hot water, where the samples with the exception of the nonirradiated sample swell showing gel formation. Thus, it appears that gel formation upon exposure to irradiation is a desirable characteristic of polymers of the present invention.

Another important feature of the present invention is the proper application of heat. Post heat treatment does not actually appear to contribute to improved soil redeposition characteristics, but it may prevent yellowing of the fabric. Effects of the heat treatment are set forth in the following example.

EXAMPLE lll Bordens commercial polyacrylic acid solution, 25 percent solids, is diluted with water to prepare a 2 percent solution. This solution is padded onto polyester/cotton (65/35) samples at about 60 percent wet pickup level. The individual fabric samples are treated as indicated in table V, being washed thoroughly with demineralized water before analysis.

invention is useful for textile material with minimum care characteristics such as wash and wear and durable press.

Having thus disclosed the invention, what is claimed is:

l. A process for improving the soiling characteristics of hydrophobic textile material comprising applying thereto an aqueous solution comprising a hydrophilic, water dispersible polymer in an amount between about 0.1 and 10 percent based on the weight of the textile material, subjecting the polymer treated textile material to between I and I0 megarads irradiation, and heating the irradiated textile material to an elevated temperature; said polymer consisting essentially of monomeric groups selected from whereHR, and R are selected from the group consisting of CO-OH;

OH, COOM, -N

CHz-CH;

s0,M and -sonvrv where M is hydrogen, an alkali metal or ammonia; provided R and R are not hydrogen simultaneously;

III.

, CONI'h, -CONHCH;OH,

where R R and R are selected from the group ctifiiiii'g'or -H, CH -C,H and -CH,CH OH, provided R R, and R are not hydrogen simultaneously, and said polymer containing group III is preswelled.

2. The process as defined in claim 1 wherein the material includes both cellulosic and hydrophobic synthetic fibers.

3. The process as defined in claim 4 wherein the textile material is a polyester/cotton cotton fabric.

4. The process as defined in claim 4 wherein the polymer is a methyl cellulose.

5. A process for improving the soiling characteristics of polyester/cotton fabric comprising applying thereto an aqueous solution of a polymer selected from the group consisting of polyacrylic acid, polyethlene oxide, polyvinyl alcohol. polyvinyl pyrrolidone, polyacrylamide, a copolymer of acrylic The preheated samples retain less polyacrylic acid than do the samples that are not preheated.

The above description and examples show that the present invention provides a novel process for improving the soiling characteristics of hydrophobic textile material. Furthermore, the invention provides for the improvement of soil redeposition characteristics of textile material formed of blends of synthetic polymeric fibers and cellulosic fibers. Moreover, the

acid and sodium styrene sulfonate, polypropylene oxide, a copolymer of ethylene oxide and propylene oxide, polyurethane, methyl cellulose. hydroxyethyl cellulose, and ethyl cellulose, said polymer being applied to the fabric in an amount between about 0.1 to 10 percent based on the weight of the fabric; irradiating said fabric to a total dosage of at least 0.1 megarad and thereafter heating said fabric between about 75 to C. for at least about 5 minutes. 

2. The process as defined in claim 1 wherein the material includes both cellulosic and hydrophobic synthetic fibers.
 3. The process as defined in claim 4 wherein the textile material is a polyester/cotton fabric.
 4. The process as defined in claim 4 wherein the polymer is a methyl cellulose.
 5. A process for improving the soiling characteristics of polyester/cotton fabric comprising applying thereto an aqueous solution of a polymer selected from the group consisting of polyacrylic acid, polyethylene oxide, polyvinyl alcohol, polyvinyl pyrrolidone, polyacrylamide, a copolymer of acrylic acid and sodium styrene sulfonate, polypropylene oxide, a copolymer of ethylene oxide and propylene oxide, polyurethane, methyl cellulose, hydroxyethyl cellulose, and ethyl cellulose, said polymer being applied to the fabric in an amount between about 0.1 to 10 percent based on the weight of the fabric; irradiating said fabric to a total dosage of at least 0.1 megarad and thereafter heating said fabric between about 75* to 115* C. for at least about 5 minutes. 